QtWebkit is a big package. So, yes, building takes a while, but without knowing your system spec and what you define as 'very long time' there can be no satisfying answer to your question._________________backend.cpp:92:2: warning: #warning TODO - this error message is about as useful as a cooling unit in the arctic

For what it's worth, on my archaic x86 MythTV systems (2005-ish Dell P4s) dev-qt/qtwebkit-5.9.1 takes about 6 hours to compile...so that's more or less a worst case benchmark. I'd love for MythTV to loose that dependency like a bad habit.

From 2002 I have installed Gentoo and KDE on 4 or 5 systems. This is the second time I have installed it on my laptop. The first time to 2 days. I do the base system one day and KDE the next. However the KDE install has never taking as long as this. Two nights back I left qtwebkit looping round from 10pm to 6am before I stopped it because it seemed to be looping round and round.

installing plasma-desktop. I started emerge plasma-desktop at 3pm 10/07/2018 on a 2Ghz i3 with 12Gb ram. It is now 7.25pm and it seems to be trying to compile "qtwebkit-5.9.1" the same warning lines scrolling over and over. How long should I leave it running?

The move from qt4 to qt5 has so far not been a good time with lots of slot conflicts forcing me to attempt a reinstall.

installing plasma-desktop. I started emerge plasma-desktop at 3pm 10/07/2018 on a 2Ghz i3 with 12Gb ram. It is now 7.25pm and it seems to be trying to compile "qtwebkit-5.9.1" the same warning lines scrolling over and over. How long should I leave it running?

qtwebengine integrates Chromium's fast moving web capabilities into Qt, and for this is a heavy package to compile

It's qtwebkit, not qtwebengine!

Yes, I was wrong, but the problem doesn't change much. Blink (chromiun browser engine) is based on WebKit then qtwebkit is also a heavy package to compile (a little less)._________________Questions are guaranteed in life; Answers aren't.